I have had a crown on a back molar for a couple years without problems. Tonight, as I was flossing my teeth, I could not, initially get the floss between my tooth and the crown because the crown had moved! There is no pain and it is not wiggly. I was eventually able to floss the area, but I am very concerned. Will I have to have the crown replaced? Is a moving crown within the normal range of acceptability as long as there is no pain? What should I do?